SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 7 days to 6 Dec 2023: India 75.8 µg/m³, China 40.4 µg/m³ and North Macedonia 33.9 µg/m³.
- 1India3 cities75.8
- 2China3 cities40.4
- 3North Macedonia7 cities33.9
- 4Hong Kong13 cities29.1
- 5Thailand9 cities27.0
- 6Czechia35 cities26.9
- 7Italy6 cities, was 2826.3
- 8Romania7 cities23.1
- 9Serbia3 cities21.6
- 10Austria29 cities20.5
- 11Lithuania3 cities20.4
- 12Slovakia27 cities20.2
- 13Bulgaria5 cities18.7
- 14Hungary7 cities17.7
- 15Chile38 cities17.6
- 16Belgium41 cities16.7
- 17Ireland3 cities16.4
- 18Mexico49 cities, was 1115.4
- 19Greece9 cities15.0
- 20Germany205 cities13.8
+ 15 more countries, 11.9 µg/m³ and below
- 26United States742 cities7.7
Not counted on this day, too few cities measured: Pakistan since 6 Dec 2023, Luxembourg since 5 Dec 2023, Martinique since 1 Dec 2023 and Peru since 17 Oct 2023.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.